Draining pool - submersible pump and reusing vacuum hose

etotfp

Member
Dec 29, 2010
16
Los Angeles, CA
Hi all,

We live in Southern California and I'd like to drain our 30k gallon, plaster pool about halfway. The goal is to bring the 70 ppm CYA down to range (and remove nitrates that the pool guy's test says are high). My plan is to get a reasonably beefy electric pump and drain into the large drain we already use for backwashing the DE filter.

I was wondering:
  1. Does a pump like the Tsurumi HS2.4S-62 make sense for this or is it more intended for shallow, dirty water? I'm just looking for something that will last a while and can push a minimum of 50GPM. It feels a little overkill but I don't want to be messing around with a 10GPM garden hose.
  2. Does it makes any sense to try and reuse the pool vacuum hose we already have? The pumps look to have a standardized 2" threaded attachment and I'm wondering if there's an adapter/reducer for the push-on 1.5"(?) end on the manual vacuum hose. It seems like this could be a common thing to do unless I'm missing something. I'm not opposed to buying a specialty hose, it's just more clutter.
Any other comments would be much appreciated. I was kicking the idea around of plugging up the skimmers and using the backwash mode of the main pump but that seemed risky just to save a few bucks.

Thanks.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
15,889
Evans, Georgia
Nitrates mean nothing to your pool. They have no affect on anything. If you have algae they may like to eat nitrates but the nitrates don't consume chlorine so we don't worry about them.
Do you have algae??

How do you chlorinate your pool??

You can rent a big ole' pump from Home Depot and lower the water.

Maddie :flower:
 

etotfp

Member
Dec 29, 2010
16
Los Angeles, CA
Thanks, Maddie. We are having issues with algae which is why the pool guy, after a couple of months of using more chlorine than he'd expect in the winter, eventually got around to testing for nitrates. They recommended draining it for the nitrates but I wanted to SLAM it first and do overnight tests. When I was calculating how much chlorine to use I found that their most recent test for CYA was at 70ppm ... so I figured I'd just drain it even if it wasn't for the reason they wanted to do it, then SLAM it.

We're using about 2 gallons of liquid chlorine per week. He was using some pucks a while back but seems to have stopped once the CYA got high. We are a family of five and use the spa every day, starting to use the pool a bit more now. 2 gallons/week does seem a bit high.

I looked at Home Depot to rent a pump and may just go with the biggest electric one they have locally. Sometimes rental can be a bit of a hassle, though, so I was also looking to buy one to see what the options are. Pumps can be handy sometimes.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
15,889
Evans, Georgia
Well, a good half drain will at least allow you some fresh water to help start the SLAM. You are gonna need to do so, but dont let pool tech folks confuse you- they want to sell chemicals and services. And his use of pucks only increased your CYA all the more.
You've got one of the endorsed test kits, yes??

Maddie :flower:
 

etotfp

Member
Dec 29, 2010
16
Los Angeles, CA
Yes I do. It's a big Taylor one (like the K-2005) with a book and everything. I can't seem to find it on the site anymore, nor the particular version I have from Taylor, either. In any case, I dusted it off on Sunday, checked the reagents, and am good to go except for the draining part.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
15,889
Evans, Georgia
Ok....well, I hope you can see that your FC is horribly low for a CYA level of 70. Have you seen this:
FC/CYA Chart
So you can see that your bottom line baseline FC should never be below 5ppm, with a goal more like 8-10ppm so that if your pool loses 2-3ppm of FC a day thru swimmers or normal summer sun burn off you're still over 5ppm.

The 0.5ppm of CC is normally good....except you still have algae, right? So we know you've got to deal with that.

Everything else is ok...... your CH is high which is not unusual in areas with high evaporation and hard water. Try to keep your pH on the low end so that it helps compensate to avoid scale. Do you know the CH of your fill water?

Maddie :flower:
 

etotfp

Member
Dec 29, 2010
16
Los Angeles, CA
Hi Maddie,

I don't know the fill water CH. I could test it, I guess. The water around here is notoriously "hard" but I don't know if that means Calcium or what. I'd assume so. To be honest, I kind of stopped measuring once the solution turned a slight tinge of blue. I don't do that test very often so I didn't know how far to take it and 700 was already 70 drops.

I put two gallons of 10% chlorine in after measuring. The pool guy had come by this morning and measured 0.5 FC and added 2 gallons of 10% as well. He also measured phosphates at 1100 and nitrates at 10 using test strips while we were chatting.

I agree that everything looks to be OK. If we're still losing chlorine then what could it be but algae? I could SLAM it but we're back to the 70 CYA discussion.

Thanks.

 

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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
15,889
Evans, Georgia
Ignore phosphates and nitrates.

Test your fill water. I'm sure your CH (yes, the hardness) is over 700 if you stopped before the end of the test. It happens often in your area and some folks manage it just fine- but thats with tight management of all parameters of chemistry.

Look at PoolMath and after you enter your test levels see what your CSI is...try to keep it towards the Negative side

You have algae so you have to SLAM and a half drain/refill will help both CH and algae issues.

Maddie :flower:
 

etotfp

Member
Dec 29, 2010
16
Los Angeles, CA
Ok, thanks. Tomorrow I'll repeat the CH test for the pool and also the fill water. Now that I know it's going to be high I can use the x25 version of the test. Using the numbers I have PoolMath says my CSI is 0.24 which is good.

We'll also plan to drain half the pool and SLAM it afterwards. This feels like plenty to do but, of course, any other ideas would be appreciated.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
15,889
Evans, Georgia
Don't bother measuring CH again... it doesn't change in a day unless you've drained and refilled with a different hardness of water.
Are you preparing for the drain and refill?? Stocking up on Liquid Chlorine??
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
2,072
Spring Valley, NY
Hasn't been mentioned but if you have a water softener add with that water. Many homes don't have the outdoor spigot connected to it.
 

etotfp

Member
Dec 29, 2010
16
Los Angeles, CA
Don't bother measuring CH again... it doesn't change in a day unless you've drained and refilled with a different hardness of water.
Are you preparing for the drain and refill?? Stocking up on Liquid Chlorine??
Right, but I was going to redo the CH measurement with the x25 version to see if I got the same number. I also want to know the fill hardness, too.

The current plan is to get the pump the Sunday after Easter, drain that day, and then start the refill. The refill will line up with the pool guy's normal time on his rotation. They said they'd rebalance the chemicals (chlorine, CYA, pH). They made a somewhat compelling argument to just drain it the whole way, squirt chlorine directly on any orange patches, let it sit, then hose it down and pump it out. To be honest, now that I've got it in my head to drain it the whole way I'm a bit more interested in the project. It'll give the family the opportunity to be a bit "hands-on".

We don't have a water softener and I hadn't even thought about it for the pool until now.
 

etotfp

Member
Dec 29, 2010
16
Los Angeles, CA
Ok, redoing the CH tests with the 10ml version (x25/drop) and using clear as an endpoint I get 575 ppm for the pool and 250 ppm for the fill.

USGS says the water table is -70 feet as of 2016. 🤷‍♂️ Seems like plenty for me.